Relonch Camera - AI-powered "camera as a service"
John's Background Switcher - Switch backgrounds to trending imgur, reddit, tumblr threads
Open Camera - Open Camera is an open-source camera app for Android phones and tablets.
Variety Wallpaper Changer - Variety is a wallpaper changer for Ubuntu which is featureful, yet slim and very easy to use.
AfterFocus - Create DSLR-style background-blurred photos
Muzei - Muzei is a live wallpaper that gently refreshes your home screen each day with famous works of art.